1. Field of the Invention
The present invention relates generally to a liquid body surface motion converting device, and more specifically to a floating wave-powered pump capable of converting random surface energy, as found in oceans, and the like, into a useful energy source.
2. Description of the Prior Art
It has long been desired to harness the wave and other energy forms found in ocean and other large bodies of water. One approach to the problem is to arrange a wave-actuated mechanism at or in the body of water, the output of which mechanism actuates an electrical generator associated with the mechanism. An example of such a device can be found in U.S. Pat. No. 2,477,691, issued Aug. 2, 1949, to E. M. Griffin, wherein levers mounted on a barge for vertical swinging motion have a float provided at an outboard end and are connected to a piston rod of an air compressor at an inboard end so as to compress air due to relative motion between the float and barge. The compressed air is used to power electrical generators disposed below decks of the barge. Such an arrangement, however, is inefficient and unsuitable for large scale operations due to size limitations on the generations and losses encountered in using compressed air.
Another approach has been proposed wherein wave motion is used to pump water to a reservoir at a location higher than the water surface level so that the elevated water can be passed downwardly through hydraulic turbines and back to the body of water from which it was pumped. An example of this approach can be found in U.S. Pat. No. 4,132,901, issued Jan. 2, 1979, to D. Crousbay.
Devices proposed for pumping water to a reservoir fall in three basic classes, two of which are closely related in that they both provide a buoy or float on a vertically swinging arm disposed outboard of a support on which the arm is mounted. The support can either be mounted on the floor of the body of water so as to be fixed in position relative thereto, or can be floating on the water and tethered to the floor of the body of water or to the adjacent shore.
U.S. Pat. Nos. 970,048, issued Sept. 13, 1910, to N. O. Harmon, and 4,171,189, issued Oct. 16, 1979, to G. Schreiber, disclose apparatus supported on the bottom of a body of water, but extend above the surface of the water so that the associated float or floats move a swing arm which is pivoted above the water. U.S. Pat. Nos. 4,023,515, issued May 17, 1977, to L. C. Tharaldson, and 4,092,828, issued June 6, 1978, to R. M. Garza, are similar in that they disclose floor supported overhead structures but provide a platform from which a plurality of swing arms and floats are extended. One disadvantage of these arrangements relates to the difficulty of providing height adjustment for the supports so as to accommodate variations in water level due to tide changes. The necessary structure for this purpose tends to clog and become corroded. More importantly, these support arrangements have difficulty in withstanding storms due to their exposed positions above water level.
Accordingly, arrangements have been proposed wherein the entire support structure is disposed under water in order to protect it from storm damage, with the swing arm also being under water and only the float itself projecting above the water surface. Examples of this arrangement can be found in U.S. Pat. Nos. 3,970,415, issued July 20, 1976, to K. Widcrantz, et al.; 4,111,610, issued Sept. 5, 1978, to H. C. Brown; and 4,163,633, issued Aug. 7, 1979, to J. A. Vriend. U.S. Pat. No. 3,289,415, issued Dec. 6, 1966, to G. E. Merrill, discloses a pump of the class specifically intended for the rather unique purpose of transporting water from melting icebergs which are themselves transported to arid areas from polar regions.
Among the disadvantages to this approach, however, is that placing the swing arm under water decreases the efficiency of operation of the device as compared to apparatus having its swing arm(s) disposed above water level. Further, much of the structure is still disposed dangerously near the water surface during storms.
U.S. Pat. No. 4,125,346, issued Nov. 14, 1978, to W. H. Pickle, discloses a floating support arrangement on which a plurality of swing arm and float assemblies are disposed. The support slides up-and-down with the tides on vertical posts. However, such arrangements are subject to binding problems thereby making the system susceptible to storm damage.
Another floating support arrangement is disclosed in U.S. Pat. No. 4,105,368, issued Aug. 8, 1978, to F. L. Waters. This device uses a floating, tethered vessel having connected thereto and radially extending therefrom a plurality of floating buoys pivotally connected to the vessel by swing arms which actuate pumps that force a hydraulic fluid from a sump reservoir to pressure accumulators on board the vessel. The pressurized fluid can then be tapped as needed to provide a source of power. This is a low volume set-up similar to those generating electricity on board a float or support, and has similar disadvantages to such arrangements.
In addition, the arrangement discussed immediately above, as well as most of the other devices mentioned, have the further disadvantage of not being able to develop power on both the up and down movements of the float and arm. On the down stroke, the weight of the float would have to equal the buoyancy of the float, an impractical situation.
Finally, the third class of devices uses a pair of similar floats connected together to form a pump. For example, U.S. Pat. No. 4,076,464, issued Feb. 28, 1978, discloses a dual wave motion pump in which a pair of floating bodies are linked by a lever whose motion serves to initiate and multiply the pumping energy of each of the bodies. This arrangement, however, is somewhat limited in volume, and would require a very large number of units to fill a hydroelectric reservoir, or the like.
U.S. Pat. No. 3,603,804, issued Feb. 16, 1979, to J. M. Casey, discloses a paired float arrangement using a pipe structure forming a horizontal axis to support the float pairs. The floats have a maximum sectional area at the water line thereof so as to enhance response to wave action and facilitate oscillation about their respective pivot axes. The unit is disclosed as being sinkable by remote control and subsequently raised to avoid storm damage.